I think the support is already somehow “mandatory”...At this very moment, I feel that I am forced anyhow to give support (and customizations, many times) just to not receive bad ratings/negative comments/refunds/etc So it’s mandatory already if you wish to stay on the market and have sales….

Items sold before 1st December 2014 are treated as follows:
If the item offered < 6 months support, then that period is honored.
If the item offered > 6 months support, then those items will be supported until 31 May 2015 (6 months from the new rules taking effect)

it should be vice versa ( the < > ):

Items sold before 1st December 2014 are treated as follows:
If the item offered > 6 months support, then that period is honored.
If the item offered < 6 months support, then those items will be supported until 31 May 2015 (6 months from the new rules taking effect)

About the paid support, I don’t know, I really feel that buyers will start to not buy items which are older than 6 months, because they will not be happy to pay for support.